Micro-optic security device with zones of color

ABSTRACT

A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 62/888,957, filed Aug. 19, 2019, thedisclosure of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates generally to anti-counterfeiting of secureand/or high value documents, such as banknotes, passports and tickets.More specifically, this disclosure relates to a micro-optic securitydevice with zones of color.

BACKGROUND

Micro-optic security devices, or devices comprising an array ofmicro-scale focusing elements and arrangements of image icons (forexample, sub-micro-scale regions of colored material) in the focal planeof the focusing elements, which work together to provide one or morecharacteristic visual effects (for example, a synthetic image having athree-dimensional appearance) have proven heretofore generally effectivein providing trustworthy visual indicia of the authenticity of valuedocuments, such as currency notes and passports.

The performance and effectiveness of micro-optic security devices asvisual level (i.e., detectable with a human eye, rather than with abanknote equipment manufacturer (“BEM”) device or other specializedmachinery) indicia of the authenticity of a document, can depend, atleast in part, on the extent to which the micro-optic security deviceprovides a visual effect which visually engages users, and to which theappearance of the security device or visual effects provided by thesecurity device is flexible and amenable to updates and revisions. Forexample, a synthetic image with dull colors or blurry features (whichcan occur when the image icon layer is out of focus) may be morefrequently overlooked by users, thereby increasing the likelihood ofcounterfeit banknotes circulating without notice. Similarly, wherechanges to a security device require expensive or time-consumingretooling of manufacturing processes, the interval between updates andrevisions to a security device used on a security document (for example,a banknote) will be greater, and malicious actors will have more timeand opportunity to try and develop counterfeits.

Thus, making micro-optical security devices more visually engaging andthe processes for making such devices more amenable to dynamicadjustment and redesign remains a source of technical challenges andopportunities for improvement in the field of micro-optic securitydevices and methods for manufacturing same.

SUMMARY

This disclosure provides a micro-optic security device with zones ofcolor.

In a first embodiment, a micro-optic security device with zonal colortransitions includes a planar array of focusing elements, an image iconlayer including a plurality of retaining structures, the plurality ofretaining structures defining isolated volumes at a first depth withinthe image icon layer, a first zone of image icons, the first zone ofimage icons having a first predefined subset of the plurality ofretaining structures, wherein the isolated volumes of retainingstructures of the first predefined subset of the plurality of retainingstructures contain cured pigmented material of a first color, and asecond zone of image icons, the second zone of image icons including asecond predefined subset of the plurality of retaining structures,wherein the isolated volumes of retaining structures of the secondpredefined subset of the plurality of retaining structures contain curedpigmented material of a second color, wherein the second color contrastswith the first color.

In a second embodiment, a method of making a micro-optic security deviceincludes applying a layer of uncured pigmented material of a first colorto an image icon layer of a micro-optic security device, the image iconlayer including a plurality of retaining structures, the plurality ofretaining structures defining isolated volumes at a first depth withinthe image icon layer, and scraping the image icon layer such thatuncured pigmented material of the first color only remains in theretaining structures of the image icon layer at depths equal to or lessthan the first depth. The method further includes selectively curing theuncured pigmented material of the first color by directing a firstpattern of light at a first zone of the image icon layer to form a firstarrangement of image icons, and removing the uncured pigmented materialof the first color.

In a third embodiment, a method of making a micro-optic security deviceincludes selectively applying a first volume of uncured pigmentedmaterial of a first color to a first region of an image icon layer of amicro-optic security device, the image icon layer including a pluralityof retaining structures, the plurality of retaining structures definingisolated volumes at a first depth within the image icon layer. Themethod further includes selectively applying a second volume of uncuredpigmented material of a second color to a second region of the imageicon layer of the micro-optic security device, wherein at least part ofthe second region contacts at least part of the first region along a wetborder on a surface of the image icon layer and scraping the image iconlayer such that uncured pigmented material of the first color issubstantially confined to retaining structures in a first zone of theimage icon layer, and uncured pigmented material of the second color issubstantially confined to retaining structures in a second zone of theimage icon layer. Additionally, the method includes curing the uncuredpigmented material of the first color and the uncured pigmented materialof the second color, wherein the first zone of the image icon layer andthe second zone of the image icon layer meet along a region of the imageicon layer proximate to the location of the wet border.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “include” and “comprise,” as well as derivativesthereof, mean inclusion without limitation. The term “or” is inclusive,meaning and/or. The phrase “associated with,” as well as derivativesthereof, means to include, be included within, interconnect with,contain, be contained within, connect to or with, couple to or with, becommunicable with, cooperate with, interleave, juxtapose, be proximateto, be bound to or with, have, have a property of, have a relationshipto or with, or the like. The functionality associated with anyparticular controller may be centralized or distributed, whether locallyor remotely. The phrase “at least one of,” when used with a list ofitems, means that different combinations of one or more of the listeditems may be used, and only one item in the list may be needed. Forexample, “at least one of: A, B, and C” includes any of the followingcombinations: A, B, C, A and B, A and C, B and C, and A and B and C.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure and its advantages,reference is now made to the following description, taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates an example of a micro-optic system according tocertain embodiments of this disclosure;

FIGS. 2A and 2B illustrate, in exploded perspective views from above andbelow, a micro-optic cell within a micro-optic security device accordingto certain embodiments of this disclosure;

FIGS. 3A through 3F illustrate aspects of the structure and manufactureof a section of a structured image icon layer according to variousembodiments of this disclosure;

FIG. 4 illustrates aspects of an apparatus for zonally curing regions ofuncured pigmented material according to various embodiments of thisdisclosure;

FIG. 5 illustrates operations of a method for making a zonally curedmicro-optic security device according to various embodiments of thisdisclosure;

FIGS. 6A through 6E illustrate aspects of the structure and manufactureof a section of structured image icon layer according to variousembodiments of this disclosure; and

FIG. 7 illustrates an example of preserving sharp color transitionsbetween zones within an image icon layer, according to certainembodiments of this disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 7, discussed below, and the various embodiments used todescribe the principles of this disclosure in this patent document areby way of illustration only and should not be construed in any way tolimit the scope of the disclosure.

FIG. 1 illustrates an example of a micro-optic system 100 according tocertain embodiments of this disclosure.

Referring to the non-limiting example of FIG. 1, micro-optic system 100comprises, at a fundamental level, a planar array of focusing elements105 (including, for example, focusing element 107), and an arrangementof image icons 120 (including, for example, image icon 121). Accordingto various embodiments, each focusing element of planar array offocusing elements 105 has a footprint, in which one or more image iconsof arrangement of image icons 120 is positioned. In certain embodiments,the locations of the image icons within arrangement of image icons 120within the respective footprint of each focusing element correspond tospaces between retaining structures in an image icon layer. According tosome embodiments, the ratio of the resolution of planar array offocusing elements 105 (for example, the number of focusing elementsprovided in a specified area, such as a 1×1 mm box) relative to theresolution of the arrangement of image icons 120 (for example, thenumber of focusing elements provided in the specified area) is 1 orgreater. As a non-limiting example, each image icon within arrangementof image icons 120 may fall within the footprints of multiple focusingelements. As a further non-limiting example, there may not be imageicons within the footprint of every focusing element within thespecified area. Additionally, in some embodiments according to thisdisclosure, the ratio of the resolution of planar array of focusingelements 105 relative to the resolution of the arrangement of imageicons 120 may have a value of less than 1. As a non-limiting example,there may be multiple image icons within the footprint of a particularfocusing element. Put differently, zones of zonally cured pigmentedmaterial according to embodiments of this disclosure can be ofsub-focusing element, and multi-focusing element scales. As used in thisdisclosure, “uncured pigmented material” encompasses polymeric inks,pigmented polymers, as well as dye-based inks which transition from awet, uncured state, to a more rigid, drier state in response to achemical reaction induced through the application of a curing light (forexample, ultraviolet curing light.

According to certain embodiments, plurality of focusing elements 105comprises a planar array of micro-optic focusing elements. In someembodiments, the focusing elements of planar array of focusing elements105 comprise micro-optic refractive focusing elements (for example,plano-convex or GRIN lenses), with a lensing surface providing a curvedinterface between regions of dissimilar indices of refraction (forexample, a polymer lens material and air). Refractive focusing elementsof planar array of focusing elements 105 are, in some embodiments,produced from light cured resins with indices of refraction ranging from1.35 to 1.7, and have diameters ranging from 5 μm to 200 μm. In variousembodiments, the focusing elements of planar array of focusing elements105 comprise reflective focusing elements (for example, very smallconcave mirrors), with diameters ranging from 5 μm to 50 μm. While inthis illustrative example, the focusing elements of planar array offocusing elements 105 are shown as comprising circular plano-convexlenses, other refractive lens geometries, for example, lenticularlenses, are possible and within the contemplated scope of thisdisclosure.

As shown in the illustrative example of FIG. 1, arrangement of imageicons 120 comprises a set of image icons (including image icon 121),positioned at predetermined locations within the footprints of thefocusing elements of planar array of focusing elements 105. According tovarious embodiments, the individual image icons of arrangement of imageicons 120 comprise regions of zonally light cured material in the spacesdefined by retaining structures in a structured image icon layer. Asused in this disclosure, the term “structured image layer” encompasses alayer of material (for example, a light-curable resin) which has beenembossed, or otherwise formed to comprise structures (for example,recesses, posts, grooves, or mesas) for positioning and retaining imageicon material. According to certain embodiments, arrangement of imageicons 120 is constructed to facilitate dynamic redesign andreconfiguration of the image icon structure of micro-optic securitydevice 100. For example, arrangement of image icons 120 is, in someembodiments, formed by selectively filling and curing retainingstructures (as shown in FIG. 1, square wells) with uncured pigmentedmaterial of one or more colors which are then cured to create regions,or zones of color within arrangement of image icons 120. In thisnon-limiting example, the different colors within arrangement of imageicons 120 are represented by different fill patterns on a surface of theimage icons most proximate to the focusing layers. For example, imageicon 121 is shown as having the same color as image icons in its row.

As shown in the illustrative example of FIG. 1, in certain embodiments,micro-optic system 100 includes an optical spacer 110. According tovarious embodiments, optical spacer 110 comprises a film ofsubstantially transparent material which operates to position imageicons of arrangement of image icons 120 in or around the focal plane offocusing elements of planar array of focusing elements 105. In certainembodiments according to this disclosure, optical spacer 110 comprises amanufacturing substrate upon which one or more layers of light curablematerial can be applied, embossed and flood cured to form retainingstructures, which can then be filled with pigmented light curablematerial which is zonally cured. As used in this disclosure, the term“filled,” as used in the context of filling retaining structures of animage icon layer encompasses both filling all of the available volume ofthe retaining structure with uncured pigmented material, but alsofilling the majority (for example, 50-80 percent) of the availablevolume of the retaining structure with uncured material. In certainembodiments, the light-curable material used to form arrangement ofimage icons 120 is a pigmented, ultraviolet (UV)-curable polymer.

In certain embodiments according to this disclosure, micro-optic system100 comprises a seal layer 140. According to certain embodiments, seallayer 140 comprises a thin (for example, a 2 μm to 50 μm thick layer) ofsubstantially clear material which interfaces on a lower surface, withfocusing elements of the planar array of focusing elements 105, andcomprises an upper surface with less variation in curvature (forexample, by being smooth, or by having a surface whose local undulationsare of a larger radius of curvature than the focusing elements) than theplanar array of focusing elements 105.

As shown in the non-limiting example of FIG. 1, in certain embodiments,micro-optic system 100 can be attached, for example, by an adhesivelayer 130, to a substrate 150, to form a security document 160.According to various embodiments, substrate 150 can be a sheet ofcurrency paper, or a polymeric substrate. According to some embodiments,substrate 150 is a thin, flexible sheet of a polymeric film, biaxiallyoriented polypropylene (BOPP). In various embodiments, substrate 150 isa section of a synthetic paper material, such as TESLIN®. According tosome embodiments, substrate 150 is a section of a polymeric cardmaterial, such as a polyethylene terephthalate (PET) blank of a typesuitable for making credit cards and driver's licenses.

FIGS. 2A and 2B (collectively, “FIG. 2”) illustrate, in explodedperspective views from above and below, a micro-optic cell 200 within amicro-optic security device (for example, micro-optic security device100 in FIG. 1) according to certain embodiments of this disclosure. Asused in this disclosure, the term “micro-optic cell” encompasses a threedimensional section of a micro-optic security device corresponding to asingle focusing element within a planar array of focusing elements (forexample, planar array of focusing elements 105 in FIG. 1). Forconvenience, structures of micro-optical cell 200 which are visible inboth the view from above presented in FIG. 2A and the view from belowpresented in FIG. 2B are numbered similarly.

Referring to the non-limiting example of FIG. 2, micro-optic cell 200 isone of a plurality (in some embodiments, millions) of micro-optic cellsforming a micro-optic security device (for example, micro-optic securitydevice 100 in FIG. 1.) According to various embodiments, micro-opticcell 200 comprises a focusing element 207. In this illustrative example,focusing element 207 is a refractive focusing element (in this case, aplano-convex lens) which is formed by applying a layer of light curablematerial to an optical spacer layer 210 (for example, a layer oftransparent film material also acting as a manufacturing substrate),embossing the layer to define the shape of focusing element 207, and insome embodiments, an additional optical spacer 201 (sometimes referredto as a “goo spacer”) and then curing the materials with light (forexample, UV light) to effect one or more chemical curing reactions toproduce a layer of material of sufficient robustness for use in amicro-optic security device.

According to various embodiments, micro-optic cell 200 further comprisesa section 220 of a structured image icon layer (for example, an imageicon layer containing arrangement of image icons 120 in FIG. 1).Referring to the non-limiting example of FIG. 2, section 220 of thestructured image icon layer comprises a plurality of retainingstructures (for example, retaining structure 230), wherein eachretaining structure defines an isolated volume having a first depth (forexample, depth 235). In various embodiments according to thisdisclosure, the image icon layer comprising section 220 is constructedusing a similar manufacturing technique as focusing element 207, whereina layer of uncured light curable material is applied to a side ofoptical spacer 210, embossed to form a plurality of retaining structures(for example, retaining structure 230), and then exposed to a lightsource to activate a curing reaction in the material to produce a curedstructured image icon layer 220.

As noted elsewhere in this disclosure, the dimensions by which theperformance of a micro-optic security device can be measured include,without limitation, the extent to which the device and optical effectsproduced by the device are visually engaging. If a micro-optic securitydevice reliably “catches a viewer's eye,” then there is a greater chancethat the absence of such a device, or irregularities in the appearanceof the device will be noticed by users. Aesthetics beget engagement, andfrom an anti-counterfeiting standpoint, engagement can be highlyadvantageous.

Experience has shown that, sharpness and presence of multiple colors ina visual effect (for example, a synthetic image) presented by amicro-optic system can drive engagement. In many cases, a micro-opticsecurity device is more likely to provide a sharp-looking visual effectwhen image icons are of a suitable thickness and are disposed within thefocal plane of focusing elements of a planar array of focusing elements.According to some embodiments, suitable image icon thicknesses encompassa range of thicknesses between 0.5 μm to 3.5 μm. In some embodiments,suitable image icon thicknesses encompass a narrower range ofthicknesses, such as, for example, 0.5 to 2.5 μm, or 1.5.-1.8 μm. Forsome applications, suitable image icons have thicknesses greater than3.5 μm or less than 0.5 μm. “Thin” icons or out-of-focus icons can leadto, without limitation, the color(s) of the synthetic image appearingwashed out, and the details of the image appearing fuzzy. Additionally,the presence of image icons in an image icon layer which are two or morecontrasting colors can drive visual engagement with a micro-opticsecurity device. However, implementing multi-colored image icons canpresent technical challenges. One method for implementing multiplecolors is to stack a first image icon layer comprising image icons of afirst color atop a second image icon layer comprising image icons of asecond color. However, this approach presents a number of technicalchallenges, such as controlling the registration of the first image iconlayer relative to the second image icon layer, and the possibility thatone or both of the stacked image icon layers fall outside the focalplane of the focusing elements. Additionally, where the system isconfigured to present a synthetic image, errors in the registration ofthe image icon layers relative to the focusing elements can present“jumps” or discontinuities in the dynamic appearance of the syntheticimage. For example, in a synthetic image comprising an object whichrotates and changes color when viewed across a range of colors,variations in the registration between the two image icon layersrelative to the focusing layers may produce abrupt, or non-sequentialtransitions between colors or in the appearance of rotation. As anillustrative example, consider a dynamic visual effect comprising asynthetic image of a multi-colored ball moving through a first position,a second position, a third position and a fourth position in response toa change in viewing angle. In some cases, when the phasing of theelements of the image icon layer is not tightly controlled relative tothe phasing of focusing elements, “jumps” or non-sequential transitionsbetween the positions of the ball may occur. In the context of theexample of a synthetic image of a ball, phasing errors may cause theball, as it appears in the synthetic image, to “jump” from the firstposition to the third position, skipping the second position, inresponse to a change of viewing angle. Another approach to implementingmultiple colors is to mechanically isolate regions of uncured pigmentedmaterial of a first color to particular locations a structured imageicon layer, blade off excess pigmented material of the first color,flood cure (e.g., unselectively expose the entire surface of the imageicon layer) the image icon layer, and then repeat this process for oneor more additional colors. The technical challenges associated withiteratively applying a region of one color, blading excess from thedevice, and then flood curing the device include smearing and stainingassociated with, for example, amounts of pigmented material of the firstcolor occupying locations within the image icon layer intended forpigmented material of the second color, and becoming cured by floodcuring before introduction of the material of the second color. Thepresence of cured material of the first color in spaces intended formaterial of the second color can make the transitions between colorsmuddy or introduce unwanted colors.

Advantageously, certain embodiments according to this disclosurecomprise image icons formed from light curable pigmented material of twoor more contrasting colors (for example, two different primary colors,such as red and green, or different shades of a same base color, forexample, black and grey). Further, certain embodiments according to thisdisclosure advantageously side-step the technical challenges associatedwith trying to achieve multiple colors by stacking image icon layers ofdifferent colors, or the technical challenges associated withiteratively trying to mechanically isolate regions of different coloredinks, remove excess ink, and then flood cure the device. Instead, visualeffects (for example, synthetic images) produced by micro-optic securitydevices according to certain embodiments of to this disclosure, exhibitsharp transitions between zones of different colors, as well as enhancedcolor saturation associated with positioning image icons within a singleimage icon layer to better ensure that the image icons are within thefocal plane of the focusing elements of a planar array of focusingelements. Further, by achieving sharp transitions between zones of imageicons of a first color and zones of image icons of a second within asingle image icon layer, the phasing of the repetition of patterns inthe image icon layer relative to the repetition pattern (for example, agrid, or hexagonal lattice) of the focusing elements can be tightlycontrolled, and “jumps” or abrupt changes in visual effects provided bythe micro-optic security device across changes in viewing angle can beavoided.

As shown in the illustrative example of FIG. 2, within the retainingstructures of image icon layer 220, there is a first zone of image iconscomprising a subset of the retaining structures containing curedpigmented material of a first color (for example, first image icon 240),as well as a second zone of image icons comprising a subset of theretaining structures containing cured pigmented material of a secondcolor (for example, second image icon 245).

FIGS. 3A through 3F illustrate aspects of the structure and manufactureof a section 300 of a structured image icon layer according to variousembodiments of this disclosure. For convenience, structures which arecommon to one or more figures of FIGS. 3A through 3F are numberedsimilarly.

Referring to the non-limiting example of FIG. 3A, a section 300 of astructured image icon layer is shown. According to various embodiments,section 300 comprises a plurality of retaining structures (for example,retaining structure 301) which define isolated volumes. In thisnon-limiting example, each of the retaining structures of section 300 ofthe structured image layer comprises a square well of a first depth, d,as shown in FIG. 3A. According to various embodiments, the shape anddepth of the retaining structures within section 300 may vary. Further,in some embodiments, the icon layer of which section 300 may compriseunstructured regions, or regions in which image icons may be formed byother methods.

In this illustrative example, a square region 310 defining a subset ofthe retaining structures in which a first zone of image icons comprisingvolumes of cured pigmented material of a first color is shown.

FIG. 3B illustrates an operation in forming a zonally cured image iconlayer according to certain embodiments of this disclosure. Asillustrated in the non-limiting example of FIG. 3, a layer 315 ofuncured pigmented material of a first color (for example, a UV-reactiveink) has been applied to a portion of section 300 of the structuredimage layer including region 310. According to some embodiments, thelayer 315 may be applied in a way (for example, by using chablons, orlithographic printing techniques) which attempts to limit theapplication of ink to retaining structures outside of region 310. Asshown in the illustrative example of FIG. 3B, in some embodiments,despite efforts to mechanically exclude ink from retaining structuresoutside of region 310, some pigmented material (for example, excess ink317) may occupy retaining structures outside of the area comprising thefirst zone of image icons. As discussed elsewhere in this disclosure, byzonally curing uncured pigmented material according to some embodimentsof this disclosure, this overflow, or excess uncured pigment does notdiminish the overall performance of the micro-optic device. Accordingly,in some embodiments of this disclosure, pigmented material of the firstcolor is applied across the entirety of section 300.

FIG. 3C illustrates an operation in forming a zonally cured image iconlayer according to various embodiments of this disclosure. Referring tothe non-limiting example of FIG. 3C, the structured image icon layercomprising section 300 is scraped (for example, by doctor blading thesurface) such that uncured pigmented material of the first colorprimarily or exclusively remains in retaining structures of the imageicon layer at depths equal to or less than first depth d. As shown inthis disclosure, in some embodiments, certain of the retainingstructures outside of region 310 will have pigmented material (forexample, 317) of the first region 310. However, it has been found thatthe advantages of certain embodiments according to this disclosure,include the fact the presence of uncured pigmented material outside of adesignated area prior to curing does not diminish the ability to producea micro-optic security device which provides a user-engaging visualeffect which includes sharp transitions between regions of color orclear, un-muddied colors.

FIG. 3D illustrates an operation in forming a zonally cured image iconlayer according to various embodiments of this disclosure. In certainembodiments according to this disclosure, the area of first region 310is selectively, or zonally cured, using patterned light 320 of afrequency or wavelength suitable for curing the pigmented material ofthe first color in the retaining structures of the structured image iconlayer to create image icons of a first zone of image icons within region310. According to certain embodiments, areas of section 300 outside ofregion 310 are not zonally cured, and pigmented material of the firstcolor remains substantially, if not entirely uncured. According tovarious embodiments, patterned light 320 is projected onto region 310 isprovided by a UV projector rendering, with UV light pixels of a digitalimage (for example, a mask file). In some embodiments, patterned light320 is projected by a rastering UV laser. In some embodiments accordingto this disclosure, patterned light 320 is projected directly at thesurface of structured image icon layer comprising section 320. Incertain embodiments, patterned light 320 is projected through focusingelements (for example, planar array of focusing elements 107 in FIG. 1)of a micro-optic security device comprising section 300. According tovarious embodiments, by zonally curing pigmented material through thefocusing elements, the directionality (for example, the viewing angle atwhich a visual effect is visible) of visual effects provided by themicro-optic device can be controlled. Additionally, in certainembodiments, patterned light 320 can be projected both through thefocusing elements and directly onto the structured image icon layer tocreate variations, within the security device, of the visual effectprovided by the strip. In certain embodiments, the underlying pattern ofpatterned light 320 can be changed dynamically, or repeatedly during themanufacturing process. For example, in some embodiments, the underlyingpattern of patterned light 320 could correspond to a serial number orbatch number for a currency note, thereby heightening counterfeitresistance by making each micro-optic security device unique to aparticular document.

FIG. 3E illustrates an operation in forming a zonally cured image iconlayer according to various embodiments of this disclosure. According tocertain embodiments, all, or substantially all of uncured material ofthe first color is removed in the area outside of region 310 is removed,leaving only image icons of a first zone of image icons of a firstcolor. In certain embodiments, the uncured pigmented of the material isremoved using a spray wash of mild solvent, leaving the retainingstructures outside of region 310 completely, or substantially free ofpigmented material (cured or uncured) of the first color. In someembodiments, by selectively, or zonally curing the pigmented material ofthe first color, the incidence of smearing, or mixing of colors of imageicons in retaining structures of the image icon layer is substantiallyreduced. Advantageously, this helps in producing micro-optic securitydevices which support visual effects characterized by sharp transitionsbetween regions of different colors and clean colors.

FIG. 3F illustrates an operation in forming a zonally cured image iconlayer according to various embodiments of this disclosure. In certainembodiments, the operations described with reference to FIGS. 3A through3F can be performed again with pigmented material of one or moreadditional colors, including second, third, fourth and further colors.Referring to the non-limiting example of FIG. 3F, the operationsdescribed with reference to FIGS. 3A through 3F have been performedagain to create image icons of a first zone of image icons 350 and asecond zone of image icons 360. In some embodiments, for example,embodiments in which the design of the security device specifies thatevery retaining structure of an image icon layer be filled with curedpigmented material, the final curing step may be performed using a floodcure, rather than a zonal cure.

FIG. 4 illustrates aspects of an apparatus for zonally curing regions ofuncured pigmented material according to various embodiments of thisdisclosure.

In many cases, micro-optic security devices and security documentsincorporating same are constructed using roll-to-roll manufacturingprocesses, wherein a web of material is unspooled from a first roll, andmechanically and physically processed as it passes through one or moremachines before being taken up on a second roll. Advantageously, imageicon layers (for example, the image icon layer comprising section 300 inFIG. 3A) can be zonally pigmented and cured as part of a roll-to-rollmanufacturing process for producing security strips.

Referring to the non-limiting example of FIG. 4, elements of anapparatus 400 for zonally curing an image icon layer of a micro-opticare illustrated. According to certain embodiments, apparatus 400comprises a projector 401, a positioning roller 410, and a positionsensor 420.

In some embodiments, projector 401 is configured to project a pattern oflight 415 upon moving web 430, as it passes from positioning roller 410to a wash station or other processing configured to remove uncuredpigmented material. According to certain embodiments, projector 401comprises a UV rastering laser, or a motion picture projector, or otherapparatus capable of projecting a dynamic (e.g., moving in sync withmoving web 430) pattern of light at a wavelength suitable for curingportions of a layer of uncured pigmented material on moving web 430. Asshown in the illustrative example of FIG. 4, moving web 430 coated witha layer of uncured pigmented material of a first color passes overpositioning roller 410 and into the projection zone of projector 401.According to various embodiments, positioning roller 410 operates tomaintain a predetermined level of tension and flatness in moving web 430as it passes into the projection zone of projector 401.

Referring to the non-limiting example of FIG. 4, position sensor 420tracks the speed and current position of reference points (for example,score marks or other position indicators) in moving web 430 relative toprojector 401 and provides positional data to a computer or othercontrol apparatus for projector 401.

According to various embodiments, projector 401 is configured to projecta pattern of curing light upon moving web 430 corresponding to zones ofimage icons of a first color as moving web 430 passes through theprojection zone of projector 401. In certain embodiments, because movingweb 430 is always moving, to realize the benefits of zonal curing, thepattern of light 415 projected by projector moves in sync with movingweb 430, such that the same or substantially the same regions of thelayer of uncured pigmented material are exposed to light as moving web430 passes through the projection zone of projector 401. By the sametoken, pattern of light 415 is projected onto moving web 430 such thatthe same or substantially the same regions of the layer of uncuredpigmented material are not exposed to light as moving web 430 passesthrough the projection zone of projector 401. Multiple instances ofapparatus 400 can be incorporated as part of a roll-to-rollmanufacturing system for micro-optic security devices according toembodiments of this disclosure. According to certain embodiments, alayer of uncured pigmented material of a first color is applied, zonallycured, and the uncured material washed off in preparation for repeatingthe process with a layer of uncured pigmented material of a secondcolor.

FIG. 5 illustrates operations of a method 500 for making a zonally curedmicro-optic security device according to various embodiments of thisdisclosure.

Referring to the non-limiting example of FIG. 5, at operation 505, alayer of uncured pigmented material of a first color (for example, layer315 in FIG. 3) is applied to an image icon layer (for example, imageicon layer 220 in FIG. 2) of a micro-optic security device (for example,micro-optic security device 100 in FIG. 1). As noted elsewhere in thisdisclosure, the image icon layer can be part of a micro-optic securitydevice using refractive (for example, an array of micro-lenses) orreflective (for example, an array of curved micro-mirrors) focusingelements.

According to certain embodiments, the image icon layer to which thelayer of uncured pigmented material is applied to at operation 505comprises a plurality of retaining structures (for example, retainingstructure 230 in FIG. 2) which define isolated volumes having a firstdepth. In some embodiments, the layer of uncured pigmented material isfilled to the first depth (e.g., “to the tops” of the retainingstructures). In some embodiments, the applied layer fills all of theretaining structures of the image icon layer. In certain embodiments,the layer of uncured pigmented material of the first color is appliedselectively, for example, by using chablons, or one or more printtechniques (for example, inkjet, offset, flexo, split fountain or screenprinting techniques) to apply uncured pigmented materials to some areas,but not others of the image icon layer.

As shown in the illustrative example of FIG. 5, at operation 510, theimage icon layer is scraped such that uncured pigmented material of thefirst color remains in retaining structures at depths less than, orequal to the first depth. For example, as shown in FIG. 3C of thisdisclosure, the excess pigmented material on top of the image icon layeris removed, and ink remains in retaining structures. According tovarious embodiments, scraping the image icon layer at operation 510 isperformed using a doctor blade. In some embodiments according to thisdisclosure, one or more solutions (for example, an oxygen inhibitorsolution) is applied to the flats, or interstitial regions betweenretaining structures to prevent pigmented material in these areas frombeing cured, so that it can be washed away.

Referring to the non-limiting example of FIG. 5, at operation 515, theuncured pigmented material of the first color is selectively cured bydirecting a first pattern of light at a first zone (for example, region310 in FIG. 3A) to form image icons of a first arrangement of imageicons. According to certain embodiments, the image icons formed atoperation 510 comprise volumes of cured pigmented material of the firstcolor at positions defined by the retaining structures of the image iconlayer.

In some embodiments, the selective curing performed at operation 510 isperformed as part of a roll-to-roll manufacturing process, wherein aprojector (for example, projector 401 in FIG. 4) is configured toproject a pattern of light which is synchronized with the movement of amoving web comprising the image icon layer. In certain embodiments, amoving physical mask which is synchronized with the movement of themoving web is used to selectively expose zones within the image iconlayer to curing light. According to various embodiments, the selective,or zonal, curing performed at operation 510 is performed by projectingthe curing light directly upon the image icon layer. In certainembodiments, at operation 510, the curing light is projected indirectlyupon the image icon layer (for example, through a planar array offocusing elements of a micro-optic security device.

As shown in the illustrative example of FIG. 5, at operation 520, theuncured pigmented material of the first color is removed from the imageicon layer. In one illustrative embodiment, operation 520 is performedby passing the image icon layer through a spray station where a mildsolvent is used to flush uncured pigmented material from the retainingstructures of a structured image icon layer.

FIGS. 6A through 6E illustrates aspects of the structure and manufactureof a section 600 of a micro-optic security device according to variousembodiments of this disclosure. For convenience and ease of referenceelements of section 600 which are visible in more than one figure ofFIGS. 6A through 6E are similarly numbered.

Referring to the non-limiting example of FIG. 6A, a top view of asection of a micro-optic security device (for example, device 100 inFIG. 1) according to certain embodiments of this disclosure is shown. Inthis illustrative example, focusing elements 601 of an array of focusingelements (for example, planar array of focusing elements 105 in FIG. 1).According to various embodiments, focusing elements of planar array offocusing elements 601 comprise lenses whose centers generally align withpoints of a planar hexagonal lattice. In some embodiments according tothis disclosure, focusing elements 601 comprise reflective focusingelements, and are arrayed according to a different pattern (for example,a square or rectangular lattice. Further, in embodiments where focusingelements 601 are refractive focusing elements, depending on theconstruction of the micro-optic security device, focusing elements 601can variously have concave or convex lensing surfaces.

Referring to the non-limiting example of FIG. 6B, a bottom view ofsection 600 of the micro-optic security device is shown. In thisillustrative example, an image icon layer 605 comprising a plurality ofretaining structures (for example, retaining structure 607) is visiblein this bottom view. As shown in this illustrative example, theretaining structures of image icon layer 605 are, like the focusingelements of planar array of focusing elements 601, arrayed in a planarhexagonal lattice. Further, in the non-limiting example of FIG. 6B theresolution of planar array of focusing elements 601 is the same, orsubstantially the same, as that of image icon layer 605, with oneretaining structure positioned in the footprint of each focusingelement. Other embodiments, with different geometries of retainingstructures, and different relative resolutions of focusing elements andretaining structures are possible, and within the contemplated scope ofthis disclosure.

Referring to the non-limiting example of FIG. 6C, uncured pigmentedmaterial 609 of a first color has been selectively applied to a portionof image icon layer 605 such that it defines a first zone of color.According to various embodiments, uncured pigmented material 609 isselectively applied using by adapting one or more techniques forprecisely applying ink to a final substrate (for example, paper or apolymeric substrate). Examples of suitable methods for applying uncuredpigmented material 609 include, without limitation, inkjet printing,offset lithography, direct lithography, flexography, as well asvariously changing the composition of uncured pigmented material 609 totune a parameter (for example, hydrophilicity) related to its ability towet image icon layer 605. According to certain embodiments, uncuredpigmented material 609 is applied such that it overflows the retainingstructures, thereby wetting interstitial spaces (for example,interstitial region 611, and forming one or more cohesive masses ofliquid with an edge (for example, edge 613) on the surface of iconlayer. Note also, that in certain embodiments according to thisdisclosure, one or more volumes (for example, volume 615) of uncuredpigmented material 609 may partially fill one or more retainingstructures within image icon layer 605.

Referring to the non-limiting example of FIG. 6D, according to certainembodiments, after uncured pigmented material 609 of the first color isselective applied to image icon layer 605, uncured pigmented material621 of a second color is applied to image icon layer 605 in an areacorresponding to a second zone of color. According to variousembodiments, uncured pigmented material 621 is likewise selectivelyprovided in sufficient quantities to not only fill the retainingstructures, but to also create one or more cohesive bodies of fluidcovering interstitial space between the retaining structures (forexample, interstitial space 623), but to also meet one or more cohesivebodies of uncured pigmented material of a different color (for example,uncured pigmented material 609) along one or more boundaries (forexample, boundary 625. According to various embodiments, becauseretaining structures in the first zone have been filled with uncuredpigmented material 609 to a suitable depth (for example, filling, orsubstantially filling retaining structures of depths in the range 1 μm-3μm) uncured pigmented material 621 of the second color is not drawn intothe retaining structures of the first zone. Thus, in certain embodimentsaccording to this disclosure, boundary 625 occupies substantially thesame location on image icon layer as edge 613.

Referring to the non-limiting example of FIG. 6E, in certain embodimentsaccording to this disclosure, the bulk, or excess, of uncured pigmentedmaterial 609 and uncured pigmented material 621 are removed from theinterstitial spaces of image icon layer 605, leaving uncured pigmentedmaterial 609 of the first color substantially in a first zone 630, anduncured pigmented material 621 of the second color substantially in asecond zone 635. While one or more retaining structures around theboundary between first zone 630 and second zone 635 may contain uncuredpigmented material of multiple colors, this does not have a significanteffect on the sharpness of color transitions achieved by a micro-opticsecurity device incorporating image icon layer 605 for at least thefollowing reasons. First, as discussed elsewhere in this disclosure, ithas been observed that retaining structures which are filled, or mostlyfilled with unpigmented material of one color, do not draw unpigmentedmaterial of another color applied to nearby regions of the image iconlayer. Second, and as discussed with reference to FIG. 7 of thisdisclosure, the effects of “out-of-zone” unpigmented material can, insome embodiments, be mitigated by zonal curing, or dilution of the“out-of-zone” material. According to various embodiments, uncuredpigmented material 609 and uncured pigmented material 621 are cured, tocatalyze a chemical reaction imparting structural stability to thematerial in the retaining structures.

Advantageously, much sharper color transitions, relative to transitionsobtained by iteratively applying, blading, and curing uncured pigmentedmaterial one color at a time, in certain embodiments, be achieved byselectively applying uncured pigmented material of multiple colors tofill substantially all of the retaining structures of an image iconlayer, removing all of the excess, and then curing multiple zones ofcolor together.

FIG. 7 illustrates a non-limiting set of examples of how certainembodiments according to this disclosure can achieve sharp colortransitions.

Referring to the non-limiting example of FIG. 7, a micro-optic device700 according to certain embodiments of this disclosure illustrated.According to various embodiments, micro-optic device 700 comprises anarray of focusing elements 701 (for example, array of focusing elements601 in FIG. 6A). In some embodiments, micro-optic security device 700further comprises an optical spacer 703 (for example, optical spacer 110in FIG. 1). Additionally, in some embodiments, micro-optic device 700comprises a structured image icon layer 705 (for example, the structuredimage icon layer comprising section 300 in FIGS. 3A-3F), which containsa plurality of retaining structures, including, for example, retainingstructure 710.

As discussed elsewhere in this disclosure, the observed sharpness oftransitions between a first region of image icons of a first color, anda second region of image icons of a second color in a visual effect (forexample, a synthetic image) produced by a micro-optic device is enhancedwhen the incidence of image icons containing cured material of differentcolors is reduced, or more preferably, effectively eliminated.

Referring to the non-limiting example of FIG. 7, the portion of imageicon layer 705 shown in FIG. 7 comprises the area around an intendedboundary 711 between a first zone of a first color (marked “A” in thefigure) and a second zone of a second color (marked “B” in the figure).

According to various embodiments, uncured pigmented material 715 (shownwith diagonal line shading) of the first color is selectively applied tothe image icon layer. As shown in this illustrative example, whileuncured pigmented material 715 is selectively applied such that itprimarily fills retaining structures in first zone “A,” in someembodiments, some of uncured pigmented material 715 (also referred toherein as “out-of-zone” color) is present in retaining structures (forexample, retaining structure 720) in second zone “B.”

In embodiments utilizing zonal curing, the effect of on the performanceof the micro-optic system from out-of-zone color from uncured pigmentedmaterial 715 can be minimized by zonally curing image icon layer 705such that only the retaining structures in zone “A” are cured, therebyallowing out-of-zone uncured pigmented material 715 in zone “B” to bewashed out before application of uncured pigmented material 725 of asecond color (shown in the figure with cross-hatching) is applied.

Similarly, in certain embodiments wherein substantially all of theretaining structures of the image icon layer are filled with uncuredpigmented material of two or more colors (for example, embodimentsdescribed with reference to FIGS. 6A-6E) the effect of out-of-zoneuncured pigmented material 715 in zone “B” on the appearance of imagesproduced by the micro-optic security device is similarly mitigated.According to certain embodiments, when uncured pigmented material 725 ofthe second color is introduced in retaining structures containingout-of-zone uncured pigmented material 715 of the first color (forexample, retaining structure 720), the uncured pigmented materials mixprior to curing, and the performance problems associated with havingpockets or volumes of cured material of two or more different colors atthe “bottom” (i.e., the portion of the retaining structure mostproximate to the focusing elements of the micro-optic device) can beavoided.

According to certain embodiments, uncured pigmented material 725 of asecond color is selectively applied to image icon layer 705 and targetedat retaining structures in second zone “B” of image icon layer 705. Incertain embodiments, amounts of uncured pigmented material 725 goout-of-zone into retaining structures (for example, retaining structure710) in zone “A.” Advantageously, it has been found that, in certainembodiments according to this disclosure, out-of-zone uncured pigmentedmaterial 725 does not affect the ability to achieve sharp colortransitions in visual effects produced by micro-optic system 700.

For example, in some embodiments where the uncured pigmented material715 of the first color is zonally cured before applying uncuredpigmented material 725, the material of the first color occupies the“bottom” of the retaining structure, and the possibility of curedpigmented material in the portion of the image icon layer most proximateto the focusing elements is avoided. Similarly, in some embodiments, theuncured pigmented material 725 of the second color is zonally cured, andmuch, if not all, of the out-of-zone uncured pigmented material 725 canbe washed away. In various embodiments, uncured pigmented material 725of the second color is flood cured. However, the presence of curedmaterial of the first color confines the out-of-zone uncured material725 of the second color to portions of the retaining structure mostdistal from the focusing elements, where its presence is substantiallyunnoticeable in visual effects produced by micro-optic security device700.

As a further example, in certain embodiments according to thisdisclosure, where uncured pigmented material 715 of the first color isinitially selectively applied to target retaining structures in zone“A,” it has been observed that, due to hydrostatic effects, retainingstructures which are filled or substantially filled with uncuredpigmented material 715 generally do not draw uncured pigmented material725 of the second color. Additionally, where uncured pigmented materialof different colors is present in a retaining structure, the uncuredpigmented material mixes, and the problems associated with havingdifferent colors of cured pigmented material at the “bottom” of theretaining structure can be avoided.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security devicescomprising a planar array of focusing elements, an image icon layercomprising a plurality of retaining structures, the plurality ofretaining structures defining isolated volumes at a first depth withinthe image icon layer, a first zone of image icons, the first zone ofimage icons comprising a first predefined subset of the plurality ofretaining structures, wherein the isolated volumes of retainingstructures of the first predefined subset of the plurality of retainingstructures contain cured pigmented material of a first color, and asecond zone of image icons, the second zone of image icons comprising asecond predefined subset of the plurality of retaining structures,wherein the isolated volumes of retaining structures of the secondpredefined subset of the plurality of retaining structures contain curedpigmented material of a second color, wherein the second color contrastswith the first color.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein the cured pigmented material of the first color in the firstzone of image icons is of a depth less than the first depth, and whereinthe cured pigmented material of the second color in the second zone ofimage icons is of a depth equal to or greater than the first depth.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein the first predefined subset of the plurality of retainingstructures corresponds to a dynamically customized display to beprovided by the micro-optic security device.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein the dynamically customized display to be provided by themicro-optic security device comprises a unique alphanumeric identifierof the micro-optic security device.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein the dynamically customized display comprises image icons fromthe first zone of image icons and the second zone of image icons.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein image icons of the first zone of image icons and image icons ofthe second zone of image icons occupy locations in the image icon layerassociated with a common phasing relationship relative to focusingelements of the planar array of focusing elements, wherein, when viewedthrough focusing elements of the planar array of focusing elements, theimage icons of the first zone of image icons and image icons of thesecond zone of image icons, present a dynamic visual effect, whoseappearance changes across ranges of viewing angles, and wherein thecommon phasing relationship of the first zone of image icons and secondzone of image icons relative to focusing elements of the planar arrayproduces sequential changes in the appearance of the dynamic visualeffect.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein pigmented material of the first color is excluded from thesecond zone of image icons.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security devicesfurther comprising a layer of cured pigmented material disposed at adepth greater than or equal to the first depth, wherein the layer ofcured pigmented material is in register with at least a portion of theplurality of retaining structures.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein focusing elements of the planar array of focusing elements arerefractive focusing elements, and wherein the image icon layer isdisposed proximate to a focal plane of the planar array of focusingelements.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein focusing elements of the planar array of focusing elements arereflective focusing elements, and wherein the image icon layer isdisposed proximate to a focal plane of the planar array of focusingelements.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein each focusing element of the planar array of focusing elementshas a footprint, wherein the first zone of image icons corresponds toportions of footprints of a first subset of focusing elements at whichthe first zone of image icons are visible at a predetermined range ofviewing angles.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein the cured pigmented material of the first color comprises alight-curable ink, wherein the light-curable ink polymerizes in responseto light wavelengths in an emission spectrum of a light emitting diode(LED) lamp.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security devicesfurther comprising a third zone of image icons comprising a thirdpredefined subset of the plurality of retaining structures, wherein theisolated volumes of retaining structures of the first predefined subsetof the plurality of retaining structures contain cured pigmentedmaterial of a third color, wherein the third color contrasts with thefirst and second colors.

Examples of micro-optic security devices according to variousembodiments of this disclosure include micro-optic security deviceswherein one or more image icons of the first zone of image icons ispositioned proximate to one or more image icons of the second zone ofimage icons, such that, when viewed through focusing elements of planararray of focusing elements, the one or more image icons of the firstzone of image icons proximate to the one or more image icons of thesecond zone of image icons appear as a region of a third color, andwherein the third color is a mixture of the first color and the secondcolor.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods comprisingapplying a layer of uncured pigmented material of a first color to animage icon layer of a micro-optic security device, the image icon layercomprising a plurality of retaining structures, the plurality ofretaining structures defining isolated volumes at a first depth withinthe image icon layer, scraping the image icon layer such that uncuredpigmented material of the first color remains in the retainingstructures of the image icon layer at depths equal to or less than thefirst depth, selectively curing the uncured pigmented material of thefirst color by directing a first pattern of light at a first zone of theimage icon layer to form a first arrangement of image icons, andremoving the uncured pigmented material of the first color.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein the imageicon layer is scraped with a doctor blade.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein theuncured pigmented material is removed with a spray wash.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods furthercomprising selectively curing the uncured pigmented material of thefirst color using a DLP UV projector, an LED projector, or a rasterizedprojection from a UV laser.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods furthercomprising applying a layer of uncured pigmented material of a secondcolor to the image icon layer of the micro-optic security device,wherein the second color contrasts with the first color, scraping theimage icon, and curing the uncured pigmented material of the secondcolor.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods furthercomprising flood curing the uncured pigmented material of the secondcolor.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods furthercomprising selectively curing the uncured pigmented material of thesecond color by directing a second pattern of light at a second zone ofthe image icon layer to form a second arrangement of image icons, andremoving the uncured pigmented material of the second color.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods furthercomprising applying a layer of uncured pigmented material of a thirdcolor to the image icon layer, wherein the third color contrasts withthe first color and the second color, and curing the layer of uncuredpigmented material of the third color.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein the firstpattern of light is directed directly at the image icon layer.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods comprisingselectively applying a first volume of uncured pigmented material of afirst color to a first region of an image icon layer of a micro-opticsecurity device, the image icon layer comprising a plurality ofretaining structures, the plurality of retaining structures definingisolated volumes at a first depth within the image icon layer,selectively applying a second volume of uncured pigmented material of asecond color to a second region of the image icon layer of themicro-optic security device, wherein at least part of the second regioncontacts at least part of the first region along a wet border on asurface of the image icon layer, scraping the image icon layer such thatuncured pigmented material of the first color is substantially confinedto retaining structures in a first zone of the image icon layer, anduncured pigmented material of the second color is substantially confinedto retaining structures in a second zone of the image icon layer, andcuring the uncured pigmented material of the first color and the uncuredpigmented material of the second color, wherein the first zone of theimage icon layer and the second zone of the image icon layer meet alonga region of the image icon layer proximate to the location of the wetborder.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein the imageicon layer is scraped with a doctor blade.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein the imageicon layer is flood cured.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein one ormore of the first zone of the image icon layer or the second zone of theimage icon layer is zonally cured.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein theuncured pigmented material of the first color is selectively appliedusing one or more of inkjet printing, intaglio printing, chablons,offset lithography, direct lithography or flexographic printing.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods comprisingselectively applying a third volume of uncured pigmented material to athird region of the image icon layer, wherein the third color contrastswith the first and the second color, scraping the image icon layer suchthat uncured pigmented material of the first color is substantiallyconfined to retaining structures in a first zone of the image iconlayer, uncured pigmented material of the second color is substantiallyconfined to retaining structures in a second zone of the image iconlayer, and uncured material of the third color is substantially confinedto retaining structures in a third zone of the image icon layer, andcuring the uncured pigmented material of the first color, the uncuredpigmented material of the second color, and the uncured pigmentedmaterial of the third color.

Examples of methods of making a micro-optic security device according tovarious embodiments of this disclosure include methods wherein the firstpattern of light is directed indirectly at the image icon layer via oneor more lensing surfaces of a planar array of focusing elements.

None of the description in this application should be read as implyingthat any particular element, step, or function is an essential elementthat must be included in the claim scope. The scope of patented subjectmatter is defined only by the claims. Moreover, none of the claims isintended to invoke 35 U.S.C. § 112(f) unless the exact words “means for”are followed by a participle.

What is claimed is:
 1. A micro-optic security device with zonal colortransitions, comprising: a planar array of focusing elements; an imageicon layer comprising a plurality of retaining structures, the pluralityof retaining structures defining isolated volumes at a first depthwithin the image icon layer; a first zone of image icons, the first zoneof image icons comprising a first predefined subset of the plurality ofretaining structures, wherein the isolated volumes of retainingstructures of the first predefined subset of the plurality of retainingstructures contain cured pigmented material of a first color; and asecond zone of image icons, the second zone of image icons comprising asecond predefined subset of the plurality of retaining structures,wherein the isolated volumes of retaining structures of the secondpredefined subset of the plurality of retaining structures contain curedpigmented material of a second color, wherein the second color contrastswith the first color.
 2. The micro-optic security device of claim 1,wherein the cured pigmented material of the first color in the firstzone of image icons is of a depth less than the first depth, and whereinthe cured pigmented material of the second color in the second zone ofimage icons is of a depth equal to or greater than the first depth. 3.The micro-optic security device of claim 1, wherein the first predefinedsubset of the plurality of retaining structures corresponds to adynamically customized display to be provided by the micro-opticsecurity device.
 4. The micro-optic security device of claim 3, whereinthe dynamically customized display to be provided by the micro-opticsecurity device comprises a unique alphanumeric identifier of themicro-optic security device.
 5. The micro-optic security device of claim3, wherein the dynamically customized display comprises image icons fromthe first zone of image icons and the second zone of image icons.
 6. Themicro-optic security device of claim 1, wherein pigmented material ofthe first color is excluded from the second zone of image icons.
 7. Themicro-optic security device of claim 1, further comprising: a layer ofcured pigmented material disposed at a depth greater than or equal tothe first depth, wherein the layer of cured pigmented material is inregister with at least a portion of the plurality of retainingstructures.
 8. The micro-optic security device of claim 1, whereinfocusing elements of the planar array of focusing elements arerefractive focusing elements, and wherein the image icon layer isdisposed proximate to a focal plane of the planar array of focusingelements.
 9. The micro-optic security device of claim 1, whereinfocusing elements of the planar array of focusing elements arereflective focusing elements, and wherein the image icon layer isdisposed proximate to a focal plane of the planar array of focusingelements.
 10. The micro-optic security device of claim 1, wherein eachfocusing element of the planar array of focusing elements has afootprint, wherein the first zone of image icons corresponds to portionsof footprints of a first subset of focusing elements at which the firstzone of image icons are visible at a predetermined range of viewingangles.
 11. The micro-optic security device of claim 1, wherein thecured pigmented material of the first color comprises a light-curableink, wherein the light-curable ink polymerizes in response to lightwavelengths in an emission spectrum of a light emitting diode (LED)lamp.
 12. The micro-optic security device of claim 1, furthercomprising: a third zone of image icons comprising a third predefinedsubset of the plurality of retaining structures, wherein the isolatedvolumes of retaining structures of the first predefined subset of theplurality of retaining structures contain cured pigmented material of athird color, wherein the third color contrasts with the first and secondcolors.
 13. The micro-optic security device of claim 1, wherein one ormore image icons of the first zone of image icons is positionedproximate to one or more image icons of the second zone of image icons,such that, when viewed through focusing elements of planar array offocusing elements, the one or more image icons of the first zone ofimage icons proximate to the one or more image icons of the second zoneof image icons appear as a region of a third color, and wherein thethird color is a mixture of the first color and the second color. 14.The micro-optic security device of claim 1, wherein image icons of thefirst zone of image icons and image icons of the second zone of imageicons occupy locations in the image icon layer associated with a commonphasing relationship relative to focusing elements of the planar arrayof focusing elements, wherein, when viewed through focusing elements ofthe planar array of focusing elements, the image icons of the first zoneof image icons and image icons of the second zone of image icons,present a dynamic visual effect, whose appearance changes across rangesof viewing angles, and wherein the common phasing relationship of thefirst zone of image icons and second zone of image icons relative tofocusing elements of the planar array produces sequential changes in theappearance of the dynamic visual effect.
 15. A method of making amicro-optic security device, the method comprising: applying a layer ofuncured pigmented material of a first color to an image icon layer of amicro-optic security device, the image icon layer comprising a pluralityof retaining structures, the plurality of retaining structures definingisolated volumes at a first depth within the image icon layer; scrapingthe image icon layer such that uncured pigmented material of the firstcolor remains in the retaining structures of the image icon layer atdepths equal to or less than the first depth; selectively curing theuncured pigmented material of the first color by directing a firstpattern of light at a first zone of the image icon layer to form a firstarrangement of image icons; and removing the uncured pigmented materialof the first color.
 16. The method of claim 15, wherein the image iconlayer is scraped with a doctor blade.
 17. The method of claim 15,wherein the uncured pigmented material is removed with a spray wash. 18.The method of claim 15, further comprising: selectively curing theuncured pigmented material of the first color using a DLP UV projector,an LED projector, or a rasterized projection from a UV laser.
 19. Themethod of claim 15, further comprising: applying a layer of uncuredpigmented material of a second color to the image icon layer of themicro-optic security device, wherein the second color contrasts with thefirst color; scraping the image icon layer; and curing the uncuredpigmented material of the second color.
 20. The method of claim 19,further comprising: flood curing the uncured pigmented material of thesecond color.
 21. The method of claim 19, further comprising:selectively curing the uncured pigmented material of the second color bydirecting a second pattern of light at a second zone of the image iconlayer to form a second arrangement of image icons; and removing theuncured pigmented material of the second color.
 22. The method of claim21, further comprising: applying a layer of uncured pigmented materialof a third color to the image icon layer, wherein the third colorcontrasts with the first color and the second color; and curing thelayer of uncured pigmented material of the third color.
 23. The methodof claim 15, wherein the first pattern of light is directed directly atthe image icon layer.
 24. The method of claim 15, wherein the firstpattern of light is directed indirectly at the image icon layer via oneor more lensing surfaces of a planar array of focusing elements.
 25. Amethod of making a micro-optic security device, the method comprising:selectively applying a first volume of uncured pigmented material of afirst color to a first region of an image icon layer of a micro-opticsecurity device, the image icon layer comprising a plurality ofretaining structures, the plurality of retaining structures definingisolated volumes at a first depth within the image icon layer;selectively applying a second volume of uncured pigmented material of asecond color to a second region of the image icon layer of themicro-optic security device, wherein at least part of the second regioncontacts at least part of the first region along a wet border on asurface of the image icon layer; scraping the image icon layer such thatuncured pigmented material of the first color is substantially confinedto retaining structures in a first zone of the image icon layer, anduncured pigmented material of the second color is substantially confinedto retaining structures in a second zone of the image icon layer; andcuring the uncured pigmented material of the first color and the uncuredpigmented material of the second color, wherein the first zone of theimage icon layer and the second zone of the image icon layer meet alonga region of the image icon layer proximate to the location of the wetborder.
 26. The method of claim 25, wherein the image icon layer isscraped with a doctor blade.
 27. The method of claim 25, wherein theimage icon layer is flood cured.
 28. The method of claim 25, wherein oneor more of the first zone of the image icon layer or the second zone ofthe image icon layer is zonally cured.
 29. The method of claim 25,wherein the uncured pigmented material of the first color is selectivelyapplied using one or more of inkjet printing, intaglio printing,chablons, offset lithography, direct lithography or flexographicprinting.
 30. The method of claim 25, further comprising: selectivelyapplying a third volume of uncured pigmented material to a third regionof the image icon layer, wherein the third color contrasts with thefirst and the second color; scraping the image icon layer such thatuncured pigmented material of the first color is substantially confinedto retaining structures in a first zone of the image icon layer, uncuredpigmented material of the second color is substantially confined toretaining structures in a second zone of the image icon layer, anduncured material of the third color is substantially confined toretaining structures in a third zone of the image icon layer; and curingthe uncured pigmented material of the first color, the uncured pigmentedmaterial of the second color, and the uncured pigmented material of thethird color.